There were some ham-fisted phone calls from Clinton backers, who questioned Richardson's honor and suggested that the governor, who served in President Clinton's Cabinet, owed Hillary Clinton his support. "That really ticked me off," Richardson said.

Still, even as he moved from Clinton toward Obama  "the pursuit was pretty relentless on both sides"  Richardson wrestled with the question of loyalty. After 14 years in Congress and a measure of fame as an international troubleshooter, Richardson was named Clinton's U.N. ambassador, then Energy secretary. "Two important appointments," Richardson said.

He finally concluded that he had done his part and had settled his debt to the former president: He had worked for Clinton's election in 1992, helped pass the North American Free Trade Agreement as part of his administration, stood by him during the Monica S. Lewinsky sex scandal, and rounded up votes to fight impeachment.

"I was loyal," Richardson said during an extended conversation over breakfast this week at the governor's mansion in Santa Fe. "But I don't think that loyalty is transferable to his wife You don't transfer loyalty to a dynasty."

He was impressed by the mostly positive tone of Obama's campaign, and grew to appreciate the substance and depth of their private conversations. The more Richardson heard from the Washington heavyweights backing Clinton, the more convinced he became of the need for a change inside the Beltway.

It has been three weekssince Richardson embraced the Illinois senator, an endorsement that continues to rankle and resonate  the significance, it would seem, going far beyond the preference of a governor from a poor, rural state.

But this is a family fight, between kin of the Clinton years, so perhaps the raw emotions shouldn't be surprising. "They're very similar in personality," said Art Torres, the chairman of the California Democratic Party, and a friend of both Clinton and Richardson. "There was a bond established and I think [President Clinton] feels a little hurt."

Attention to the endorsement might have quickly passed but for the strenuous protest of Bill Clinton and others. Speaking for the campaign, strategist Mark Penn suggested Richardson's endorsement came too late to be much help to Obama. "Everyone has their endorsers," he said. But then James Carville, the pundit, strategist and longtime Clinton loyalist, hurled a lightning bolt by comparing Richardson to Judas and his surrender of Jesus for 30 pieces of silver.

Soon after came an odd back-and-forth concerning a private conversation in which, supposedly, either Hillary Clinton or Richardson dismissed Obama as unelectable. (Neither party will discuss particulars, but Richardson said he never made that statement.)

Days later, just when interest in the endorsement seemed to wane, former President Clinton exploded in a rant about Richardson at the state Democratic Party convention in San Jose. He later apologized, but his tirade in a closed-door session with superdelegates rekindled the story for several more days.

People close to Clinton said he views the governor's act as a personal betrayal. "I think [Richardson] really owes a big chunk of his success and his career to the Clintons," said an associate who has discussed the matter with the former president. and requested anonymity to speak candidly.

"Look," Richardson responded, "I was a successful congressman rescuing hostages before I was appointed. I was a governor afterward, elected on my own."

Even more than the endorsement, Clinton's associate said, the former president was angry because he felt Richardson broke his word. The two men watched the Super Bowl at the governor's mansion  Clinton made a special round-trip from California in bad weather  and the former president walked away convinced that Richardson would endorse his wife or, at least, stay neutral.

Richardson was, in fact, close to backing New York Sen. Clinton that day, though his advisors  many of whom backed Obama  urged him to wait. "I remember talking to the president and saying, 'I'm leaning. But I'm not there yet.' He denied pledging neutrality if he changed his mind. "Sometimes people hear what they want to hear," Richardson said.

Normally the most gregarious of politicians, the governor was subdued as he slowly worked his way through a plate of scrambled eggs, bacon and green chiles. His voice was soft, and he rarely smiled.

His endorsement had been highly coveted, due largely to his stature as one of the country's most prominent Latino leaders. The pursuit began soon after Richardson quit the presidential race on Jan. 10.

He retreated to New Mexico and the governor's adobe mansion. He sulked a bit, grew a beard, rode his quarter-horse and tended to state business. "I didn't want anything to do with national politics," Richardson said, figuring he would keep out of the nominating fight until it was over. But slowly he reengaged in the race, watching the debates and fielding calls from Clinton, Obama and their surrogates.

Their manner of courtship  one wooing, the other arm-twisting  seemed to reflect the candidates' different personalities and campaign styles.

Obama preferred the soft sell, calling Richardson every three days or so  "dialing the phone himself, no operator"  for long discussions about policy and campaign issues. The two developed a bantering relationship, building on the camaraderie they shared off-camera during debates, when they would roll their eyes at some of their rivals' sillier statements.

Clinton was more persistent and tactical. There were eight or more phone calls a day, Richardson said: "Bill calling. Hillary calling, friends of mine that were in the Clinton administration, Clinton operatives, Clinton Hispanic operatives, New Mexico Clinton Hispanic operatives."

Some callers  who suggested Richardson had an obligation to back Clinton  did more harm than good. "I think the Clintons have a feeling of entitlement that the presidency was theirs," Richardson said, and the persistent lobbying from "Washington establishment types" convinced him of a need for some fresher faces inside the Beltway.

He began admiring Obama back when they were rivals, and the sentiment grew the more they talked about foreign affairs, the environment and other issues. "I saw real growth in the guy," Richardson said, "a tremendous growth in policy and expression and experience."

And no, Richardson said, there was never any talk of the vice presidency, or any other job in an Obama administration. "I never say never in politics, but I'm not pining for it," Richardson said. (Nor, he suggested, would he settle for just any Cabinet post, having served before.)

With his mind made up  and dreading the conversation  Richardson called Sen. Clinton just a few hours before his endorsement of Obama was announced. He sat in his den, smoking a cigar with ESPN in the background. Their discussion, Richardson said, "was proper but heated."

The two have not spoken since. Nor has he heard from Bill Clinton, who told people he was upset that Richardson did not call him as well. (The governor said he tried, but never got through.)

The response from the Clinton camp  "the ferocity, the intensity"  has surprised him, Richardson said, though he knew he risked fracturing his relationship with the couple. His wife, Barbara, had warned him, he said; Richardson moved his hands apart, as if to signify a break.

"She also has great affection for the Clintons," the governor said, decorating their home with photographs of the Clintons and Richardsons together.

"He's very much a part of my life," Richardson said of the former president. The pictures are still hanging in the mansion's private quarters.